Problematic ancestry of General Timothy Burr, Jr. (1772-1832)

Hello Burrs: I am descended from General Timothy Burr - his daughter Harriet Elizabeth married AS Barnes of publishing fame, my ggggrandfather.

Based on "A General History of the Burr Family", General Timothy Burr's father was Timothy Burr Sr. of Hartford who it says died 1779 at age 50, son of Moses Burr, son of Thomas, son of Thomas, son of Benjamin the emigrant.

However, something isn't adding up.Timothy Burr Sr should have been born in 1729 if he died at age 50. Yet the Timothy Burr son of Moses was born in 1749. If he had been born in 1729., his father Moses would have been only 15. So there's something screwy going on.

Anyone else on this line and confused? Or anyone else who has puzzled over "A General HIstory" and has found a solution to this problem?